Pen Pals
by AnimeFanGirl453
Summary: Frisk has been sending letters to a certain monster that lives in Underground. Sans has been sending letters to a certain human that lives on the Surface. They both wish they can see each other. How happy will they be when they do? Bad summary. [One-shot] [Sans x Frisk] [Frisk x Sans] [Frans]


Frisk sat quietly while tapping her pencil against her desk. She was in deep thought, thinking about what to say. Her hand began to move and just let her thoughts flow as she wrote on the blank piece of paper.

_Dear Sans,_

_I'm fine thank you. It's really lonely though. I believe in the last letter I told you I was in an orphanage correct? I don't feel like I belong here. I really wish we can meet, but sadly I'm on the surface and you're in the underground because of that stupid barrier. You don't sound like a bad monster. I bet you don't even look that scary._

Frisk smiled at the thought of imaging the kind of person - not monster, Sans is.

_How are you and your brother Papyrus by the way? I hope things are going much better for you than it is for me._

She continued writing her thoughts. There were times she would scratch out some words because she made a mistake or it sounded too dumb to make sense. Frisk always smile though when she's writing to him. In his letters he sounds like he genuinely cares about her and the life she's living in. It make her happy to just believe that someone in her life cares about her.

Sans also believes Frisk actually cares. He opened his mailbox to see a letter, already knowing who it was from. He took it out and quickly ran back to his room to read it. He frowned as he read the beginning to know she was lonely. He chuckled when he saw a bad pun. He smiled at the end.

_I hope one day we'll meet._

_-Frisk_

He folded the letter the way it was originally folded, putting it back inside the envelope and placed it inside a box filled with letters that was all from Frisk. Her letters are unique to him. They would have a purple and blue stripe going down the envelope. He liked that. Unique like her. He took out a piece paper and a pencil, writing back to her.

_Sup, kid._

_I'm sorry I'm not there physically to keep you company but always know I'm here for you to talk to. Papyrus is coming up with a new puzzle like always and well me, I'm being the lazy bones I am believe or not._

Sans and Frisk has been pen pals for quite awhile. Almost a year and they haven't even seen each other or weren't able to show each other what they look like. They wouldn't bother describing what they look like because it wouldn't really matter what they look. They would only care about seeing them in general.

The only thing they've seen from each others world are postcards they would rarely send each other.

A postcard would have a picture of Snowdin and the other postcard would have a picture of a village. Days go by and they would wait for each other's letters to arrive and wait for the other to respond. There would be times where they would wait for at least a month before getting response. They figured it was because of either of them of didn't have the time to check their mailbox or have the time to respond.

But they just knew they would eventually receive a letter.

Although, this time it's different. It's been over a month since Frisk received a letter from Sans. She started to get worried and thought something happened. She tried to convince herself that she's just overreacting and he's probably busy with whatever.

She sighed and walked outside. She decided she'll continue to wait for him.

Frisk really wanted to see Sans one day and actually be with him. He was good to her. He feels like an actual friend, but maybe something more.

She sat outside on a bench watching the kids from the orphanage play together. Every time she tries to play with them, they would get a little skeptical because how differently she behaves compared to the rest of them. She thinks it's because she's no fun.

She sighed at the thought and laid on the bench looking at the clouds that were slowly moving.

'I wanna see Sans...' She thought. She thought about the letters he sent her, all his terrible puns made her laugh even right now while thinking back.

_Also next letter I hope to tell you something...I wish it was in person, but I guess it'll have to do._

_I hope to see you one day._

_-Sans_

Frisk blushed bright red and covered her face from embarrassment. For some reason that part made her really excited and anxious. And knowing that Sans also wanted to see her just as badly makes her really happy.

Sans makes her happy.

She smiled at that thought. She sat up from the bench and looked at Mt. Ebott where the monsters are kept.

She is filled with determination.

* * *

"SANS! Hurry up we're gonna be late! This is the first time King Asgore has invited us! ME of all people, THE GREAT PAYRUS! To his castle. I hope he doesn't freak out after meeting such a cool guy like me." Papyrus said in his confident tone.

Sans just smiled. "Yup. I wonder what he wants." He said.

Sans didn't really think about what King Asgore was going to say to them. He wasn't that worried, but the entire time on their way to him, he thought about Frisk. Often times he would think about what she looks like, what she sounds like and most importantly if she's okay right now. He mentioned in his last letter he has something to confess about.

Sans slightly blush and took a deep breath. 'C'mon now, it's fine. I can do this. It's only through a letter.' He thought.

He couldn't wait to write that letter.

The skeleton brothers arrived at the room where King Asgore was waiting. They saw him watering his golden flowers.

King Asgore was humming. Papyrus coughed to get his attention and the king turned around.

"Oh, you've arrived. Forgive me. I was busy tending my flowers here. Would you two like a cup of tea?" The King offered.

"Ooh that sounds amazing! Of course we will like a cup!" Papyrus responded with joy.

They sat down and Papyrus received a cup of tea. Sans declined. "Sorry I'm not really a tea person."

King Asgore shrugged. "That's okay. Everyone has their preference." He sat across from the brothers.

"Now listen, I'm only telling you this because you guys patrol Snowdin, a place right after the Ruins where humans would fall in." Asgore stated.

The brothers nodded and continued to listen. "...I can almost break the barrier." Asgore confessed. "I currently have 6 souls, I just need one more. For some reason, I feel like another human will fall in the underground soon. And when that happens, please either let me know or do the job yourself."

They knew what that last part meant. Sans sulked into his seat. He remembers his promise to Toriel who was behind the door that leads to the ruins. Toriel has asked Sans to keep it a secret and he will do so. And of course, he has a really good friend from the surface who's human. Killing one would just make him feel guilty and...a monster.

Papyrus stood up and saluted. "Of course your highness! We will do everything we can to give you another soul to finally release us from the underground!" He said. He nudged his brother.

Sans sighed and gave a smile to Asgore. "I'll do my best."

When the two brothers arrived back at Snowdin, Sans nervously began to write his letter to Frisk. He just let his feelings run through the page. After he finished he told Papyrus he was going to go somewhere real quick. He headed down to the post office.

Although when he arrived, he was shocked to see it was closed. It looked like it was under construction. He looked on the note on the door.

_Under construction. I don't know when it'll be done plus it's not like a lot of people even send letters nowadays_

Sans shook his head out of disbelief. Now what should he do? He can't see Frisk and the building doesn't look like it'll done anytime soon...He sat down leaning his back against the building.

He banged his skull a few times on the wall. "No. No. No." Sans looked at the envelop and showed a sad smile at it. "Maybe it was just not meant to be..."

* * *

Frisk carefully stood at the edge of a hole that leads to the Underground. She could feel herself shaking in fear and her legs were wobbling.

"Oh my god I'm crazy. Haha! I'm really about to do this..." She took another glance at the hole again. She couldn't tell how far down it was or if there's even a safe place to land on because it was too dark to tell.

She knew one thing for sure though. She wanted to see Sans and to know if he's okay. She clutched her hands into a fist. She took a deep breath and jumped down. Frisk screamed on her way down till she finally hit the ground. To her surprise, she survived the fall. She looked down and noticed she landed on a bed of golden flowers. She stood up and saw a dark hallway.

"Man the underground needs more light." She said to herself, feeling exhausted already.

She looked at the hole she fell from. 'Too far to climb back up. Too late to turn back now.' Frisk began her journey.

* * *

Everyday Sans would come by to the post office to see if anything has changed.

"Barely anything hasn't been touched..." He said to himself. He kicked the snow and just began to walk to Grillby's. He sat down and exchanged a few words to his friend.

Sans looked around at his environment. 'Frisk might enjoy it here.' He smiled to that thought, thinking about how much fun they'll have together. Especially the thought of seeing her smile.

Time flew by and it was already night time. Sans didn't feel like walking so he just teleported back to his room and laid on his mattress. He heard from downstairs his brother Papyrus cooking Spaghetti again. He smiled to himself because of how much he admires Papyrus determination.

Sans's eyelids started to become heavy. He thought about Frisk and wondered if she's okay. He felt really bored and lonely without talking to Frisk. Yeah he has his friends and his brother, but it wasn't the same with Frisk. Even through paper and without seeing each other, it made him really happy.

Compared with Toriel, they didn't really see each other either and they would just make puns and bad jokes together. They were good friends for sure, but speaking about private life was hard for Toriel and felt like she couldn't fully trust him. He understood that though. Everything just felt different with Frisk.

He smiled. He realized his feelings for Frisk about a month ago, but sadly he wasn't able to tell her. He closed his eyes and finally fell asleep.

The next day, Sans started the same routine he does almost everyday. He sat at his post and laid his head down on his arm. Everyday him and Papyrus would wait for a human to fall down and they would do their best to stop them. Sans just thinks it's too much work all for a human soul to get out of the barrier. The more he thinks about it though, the more he thinks about the sooner he can see Frisk in person. He smiled again to that same thought of seeing her.

Just when Sans was about to fall asleep, he heard something from a distance. A door opening. He knew that door was from the Ruins and he knew that Toriel wouldn't want to come out from the ruins.

'Someone else came through the door.' Sans thought. His left eye turned blue and he teleport near the door. He was right. The door was slightly open, but he saw it closed itself. He hoped it was Toriel. He turned his head and saw a human walking down the snowy path. They looked really anxious.

Sans began to walk behind them from a distance. But the more he looked at the human, the more he got this weird feelings he knows them. The human stopped their tracks when they arrived at the gate, probably thinking there was a puzzle to solved since it looked too easy to go through.

The human froze in place though when they heard footsteps slowly creeping behind them. Frisk didn't know what to do. Should she run? Beg for mercy? Cry? Hell she feels like crying because of how scared she is right now. She doesn't know what kind of monster is behind her or what they'll do.

She turned around and saw the figure was standing behind her. She screamed by how close he was and fell on her bottom.

"Hehe, sorry kiddo. I didn't mean to scare you like that. You okay?" The skeleton asked. He offered his hand to help Frisk up. She hesitated a bit, but she took it.

She stood up and took a better look at the kind of monster the skeleton is. Sans also took a good look at the kind of human she was.

'They seem kind...and familiar.' They both thought.

"Anyways, you're a human right? That's hilarious. I'm-" Sans got interrupted by seeing his brother coming down the path. "Well we gotta cut the introduction short. Follow me, bucko." He said.

Frisk smiled at how kind and gentle the skeleton was. She nodded and followed his instructions. Sans told her to hide behind the conveniently shaped lamp and told her to wait. She did so and listened to the conversation when Papyrus approached Sans.

"Brother! I swear you're never at your post when you're suppose to! You are such a lazy bones!" Papyrus lectured him.

Sans shrugged. "What can I do about it? I'm made out of bones after." He winked and Papyrus just sighed.

"Oh Sans, why do you make this so difficult to-"

"Did you say Sans?" Frisk said, popping out of her hiding spot.

Papyrus gasped. "A LAMP!? Wait no, that's not right..."

Sans and Frisk stared at each other for a bit. Frisk couldn't believe it. 'It's him.' She thought.

Sans shrugged. "Guess the cats out of the bag. Yup, I'm Sans, Sans the Skeleton. Sorry for not giving you a proper introduction, but dontcha think you could've waited a bit longer?" Then Sans was surprised to see the human running towards him and giving him a big hug.

"Whoa, whoa, whoa." He pulled Frisk away. "What's with the all hugging?" He asked feeling confused and a bit awkward.

Frisk blushed realizing she was going a bit too fast. "S-sorry...but it's me Sans. Frisk." She said. She pulled out an envelop and Sans eyes widen. He knows that envelope anywhere.

'It's her. It's really her...' Sans thought. His eyes soften and brought Frisk back into a hug. "Well what do you know, it really is you Frisk." He said softly.

Frisk hugged him back. "I'm actually hugging you..." She said out of disbelief.

After what felt like forever of hugging, Papyrus coughed and the two quickly pulled away from each other, blushing. "As much as I love this little moment you two are having, I would really appreciate it if you would tell me what's going on." Papyrus said.

"Hang on, yeah...what are you doing here Frisk? I thought I mentioned it to you that humans shouldn't be here in the underground." Sans said. He started panic. "Oh no...that means you're stuck here and Asgore said he had a feeling a human will fall.. You're a human and-"

"Sans." He stopped and looked at Frisk who was smiling. "I know. Toriel told me when I was in the ruins. It is a shame I can't go back and there is that possibility I might run into Asgore and all, but..." Frisk gently took both of Sans's hand and intertwined it with hers. She continued to smile brightly. "It's okay because I get to see you."

Sans blushed bright blue and chuckled. "You're crazy."

* * *

Sans and Frisk explained everything to Papyrus once they arrived to the brothers house. They told him how long they've messages each other and how it started.  
It all started when Frisk was told that the post office now delivers and receives letters and packages from the Underground. In her orphanage, the lady in charge offered her children to send letters to monsters in the Underground to possibly know them better. Frisk was the only one who volunteer.

_Hello stranger. My name is Frisk. I'm from the Surface. How is it over there? How are you? I hope to hear a reply and know more about you soon._

When Frisk's first letter was sent to the Underground, the letter was on a bullet board in Grillby's. Sans noticed the letter and asked Grillby about it. He said it was a letter from the Surface. Sans was very curious about what was inside the letter and why would a human bother sending a letter to the underground. He took it down from the bullet board and read it.

"It was a very simple letter." Sans said, but smiled as he continued explaining. "But it made me curious to know the kind of person behind the letter. So I responded."

_Sup, kiddo. Least I assume you're a child writing this. My name is Sans and I'm a skeleton from the Underground. It's cold from where I live but I don't have skin, so that doesn't matter too much. There's not much to say about me besides writing this letter is making me tired already. Heh, I'm kidding. I hope to learn more about you too, Frisk. _

Papyrus smiled after they finished. "My that's wonderful! I can't believe this entire time my brother was speaking to a human from the surface! And the fact you two are meeting for the first time?! This calls for some celebration spaghetti!" He announced and started working in the kitchen.

Sans leaned backed on the couch and turned to Frisk. He took another look at her. 'She's more beautiful than I imagined.' He thought while slightly blushing. He frowned though.

Frisk turned to him and noticed. "What's wrong?"

"I just, hope you'll be okay down here. Especially if one day you ever run into King Asgore." Sans said.

Frisk gave him a gentle smile. She placed her hand over his that was resting on his leg. "Sans, I'll be okay. We can deal with King Asgore later. Right now my goal was to meet you and be with you." She said.

Sans's eye soft and nodded. He intertwined his hands with hers, causing them both to blush. "Yeah...Okay."

"Wait hang on, you still have some explaining to do. Why haven't you sent me a response?" Frisk asked pouting. "You know how worried I was? I thought something bad happen!"

"Hehe sorry kiddo. The post office was closed down and still is till this day. Believe me, I was worried about you since I couldn't reach you at all or couldn't even see you. I'm sorry." He said.

Frisk continued to pout and crossed her arms. "I'm still mad."

Sans sighed, but smiled by how cute she is. "You'll forgive me eventually."

Frisk rolled her eyes. "I'm going to use the bathroom." She said. She got up from the couch and headed upstairs.

She opened a door that didn't lead to the bathroom, but instead to a messy room. She walked in and had a look around, trying to figure out who's room she just walked into, already distracted from her original destination. She walked up to a desk and noticed a small box with the lid not completely on. Frisk had a big urge to open it and so she did.

"This is Sans room." She said to herself after seeing a bunch of letters that was from her. "He kept all of it..." She felt like crying, but with joy. It made her really happy to see he didn't just throw her letters away.

Then, in the corner of her eye she saw a letter that wasn't in the box or wasn't even her letter she sent to Sans. She took a look at where the letter was addressed to.

_The Surface  
Frisk_

'A letter for me? From Sans?' She thought. Frisk also noticed it was dated over a month ago. She quickly looked around the room to make sure it was safe to open it. "Well it's address to me, right?" She ripped open the letter and began to read.

_Hey kiddo,_

_So you like tea huh? That's interesting cause I'm not that big on tea, well I'm not that big on coffee either. But I do like ketchup. __It may be weird for you, but for me it's like tea or coffee for most people. Hehe. I'm doing alright, thanks for asking. I hope the same is for you when you get this letter. I'm suppose to be on watch for humans again right now, but I know we won't have to run into them any time soon. I really rather not do work._

_Anyway, I wanna be serious about something. You know how I mention I have something to say? Well, I just hope this doesn't change your view of me or ruin anything between us. Basically, I really enjoy writing to you. It makes me happy to have you in my life. I know it's stupid, but you make me feel something I don't feel with anyone else._

Frisk's heart started to beat faster and feel like her face is burning. She continued to read.

_Imma just be straight with you and say I like you Frisk. Like in a romantic way. More than a friend. Does that make sense? Sorry...but I know we can't really see each other, but I couldn't hold myself back from telling you. Heh, it's okay if you don't feel the way. I just...I don't know and I don't even know why I'm writing still...I don't know what else to say...I just know that it's stupid to like you and to confess to you right now, _

_but I know I really do like you._

_-Sans_

"Kiddo, you in here?" Sans said opening the door to his room. He saw Frisk blushed dark red. She quickly hid her face with the letter, feeling extremely shy but also really happy to know how Sans really feels about her.

Sans was confused at first, but then noticed an open envelope and the letter in Frisk's hands. After putting two and two together, he realized Frisk opened the letter he was suppose to send her. He blushed dark blue and quickly closed the door for privacy to talk to her. He pulled the letter out of her hands. Sans was extremely embarrassed.

"You read it, didn't you?"

Frisk panicked. "I-I didn't mean to! I lost my way to the bathroom, but then I just stumbled upon to your room then I saw your letter and then...yeah...I read it..Plus it was addressed to me so..." She said softly. She started to fidget with her fingers. "I didn't know you felt this way."

Sans sat on the floor, still blushing. He didn't want to look at her. "Yeah...Go on laugh all you want. I know it's stupid." He said sighing.

"What? What makes you think it's stupid? And that I want to laugh at you?"

"Cause it is stupid and because it's stupid you want to laugh." Sans said.

Frisk shook her head and sat on the floor beside him. "I don't think it's stupid at all actually."

Sans scoff. "You're just saying to just let me down easily. Trust me kid, I can take it."

Frisk started to get frustrated by how stubborn he is to understand. "Oh, you can take it?" Sans nodded. "Yup. Bring it on."

And so Frisk did. She turned Sans's head to face hers and brought her lips to be in contact with his. Sans was taken back by the sudden action. Frisk pulled away to see his surprise expression, but to also see how blue his face is becoming. Although, Sans also saw Frisk was red as a tomato. His eyes soften after seeing how embarrassed she is and the love in her eyes.

Their foreheads touched. "I love you Sans.." Frisk said softly.

Sans gently placed his hands against her cheek, holding her head. He slowly leaned in. "I love you too Frisk."

The kiss was sweet and gentle. Even after parting, they were still blushing but smiled at each other.

"Hehe, you're a tomato." Sans chuckled.

"And you're a blueberry." Frisk smirked.

Sans went back in for another kiss. "Let's make purple then."

* * *

**Thanks for reading! Review! **


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